1. Field of the Invention
This invention relates generally to an array of light beams used to generate a pattern of spots, for example as can be employed in laser surgery and laser dermatology.
2. Description of the Related Art
In laser surgical applications, for example in laser dermatology, an optical system generates a light beam(s) of a desired size and energy and this light beam is used to treat a selected region of the patient's body (i.e., the treatment area). For example, in many dermatology applications, a hand piece is used to guide the laser beam to the treatment area. The hand piece is typically attached to one end of an articulated arm, which transmits the laser beam to the hand piece and also supports a wide range of motion for the hand piece.
A physician typically treats the treatment area by sweeping the laser hand piece back and forth over the treatment area. In many cases, the physician is guided by an aiming line, which may be generated by the hand piece. The sweeping may be either manual or automated. Automated sweeping can be achieved by mounting the laser or other light source on a movable carriage. Whatever the mechanism, as the laser beam is swept over the treatment area, the physician typically pulses the laser beam on and off, either manually or via automatic means, thereby regulating the exposure of the treatment area and creating a pattern of treatment spots over the treatment area.
Many laser technologies for dermatology use a single high power beam that is scanned across the treatment area to create a pattern of exposed areas or spots. In many cases, the spots overlap sufficiently that the entire treatment area is exposed. The treatment rates achievable by scanning a single beam in this manner can be sufficiently fast when a high power laser (typically>10 W) is used with a large diameter beam (typically 2–6 mm).
However, new treatments can use smaller spot sizes and more spots. For example, see co-pending U.S. patent applications Ser. No. 10/367,582, “Method and Apparatus for Treating Skin Using Patterns of Optical Energy,” filed on Feb. 14, 2003; and Ser. No. 60/486,304, “Method and Apparatus for Fractional Phototherapy of Skin,” filed Jul. 11, 2003; both of which are incorporated herein by reference. Traditional laser systems are not well suited for these applications because the laser beams generated by traditional systems typically are too large and too energetic. Traditional systems also are typically based on more expensive types of lasers and do not take advantage of lower power, cheaper semiconductor lasers. In addition, the single laser beam generated by traditional systems would have to be individually positioned to generate each of the spots in the overall pattern and, since there typically are a large number of spots in the pattern, the required scan time becomes unacceptably long.
Hence, there is a need for devices and methods that can generate a pattern of spots on a treatment area, preferably in an efficient manner.